Abstract: We discuss the conditions to realize a scenario of strong thermalleptogenesis, where the final asymmetry is fully independent of the initialconditions, when both heavy and light flavor effects are taken into account. Inparticular the contribution to the final asymmetry from a residual initialpre-existing asymmetry has to be negligible. We show that in the case of ahierarchical right-handed RH neutrino mass spectrum, the only possible way isa N 2-dominated leptogenesis scenario with a lightest RH neutrino mass M 1 <<10^9 GeV and with a next-to-lightest RH neutrino mass 10^12 GeV >> M 2 >> 10^9GeV. This scenario necessarily requires the presence of a heaviest third RHneutrino specie. Moreover, we show that the final asymmetry has to bedominantly produced in the tauon flavour while the electron and the muonasymmetries have to be efficiently washed out by the lightest RH neutrinoinverse processes. Intriguingly, such seemingly special conditions forsuccessful strong thermal leptogenesis are naturally fulfilled withinSO10-inspired models. Besides the tauon N 2-dominated scenario, successfulstrong thermal leptogenesis is also achieved in scenarios with quasi-degenerateRH neutrino masses. We also comment on the supersymmetric case. We also derivean expression for the final asymmetry produced from leptogenesis taking fullyinto account heavy neutrino flavour effects in the specific case $M 1\gg10^{12}\,{ m GeV}$ heavy flavoured scenario, a result that can be extendedto any other mass pattern.